The present invention concerns a method for estimating the quantity of an analyte contained in a liquid.
The invention also relates to a system for estimating the quantity of an analyte contained in the liquid.
The invention in particular relates to the field of lensless imaging of the beam lighting the fluid chamber, in order to characterize a liquid, such as blood.
The invention in particular applies to the estimation of the quantity of a D-dimer contained in the liquid. D-dimer is a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. D-dimer is therefore a fibrin degradation product.
D-dimer concentration is usually determined by a blood test to help diagnose thrombosis, in particular for patients with suspected thrombotic disorders. A positive result may indicate thrombosis but does not rule out other potential causes. Therefore, this test is essentially used to exclude thromboembolic disease where the probability is low, and in addition, to diagnose a blood disorder disseminated intravascular coagulation.
Known from document EP 2,233,923 A1 is a characterization method and system for characterizing a variation in the speed of particles or agglomeration of particles, the particles, such as blood particles, being contained in a liquid. The described method aims to characterize the coagulation or sedimentation dynamics of a fluid containing blood. The system for implementing this method comprises a fluid chamber receiving liquid, a spatially coherent light source capable of emitting a lighting laser beam. The laser beam extends in a longitudinal direction towards the fluid chamber.
The system also comprises an image sensor, such as a matrix sensor of the CCD (Charged-Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) type, arranged to make it possible to acquire a temporal series of images of an optical granularity pattern created by the interaction between the particles contained in the chamber and the laser beam. The characterization system also comprises a processing unit for processing said temporal series of images.
The distance between the fluid chamber and the image sensor in the longitudinal direction is several centimeters or tens of centimeters. The laser beam emitted by the spatially coherent light source has a surface comprised between 10 μm2 and several mm2 along a plane perpendicular to the longitudinal direction and passing through the fluid chamber.
Such a system and method make it possible to effectively characterize the coagulation or sedimentation dynamics of the blood contained in the liquid.
However, such a system is relatively bulky. Furthermore, it makes it possible to observe the coagulation phenomenon only in a relatively small volume of the fluid chamber. In addition, this system is not adapted for estimating the quantity of an analyte contained in a liquid.